Separation assembly for drug delivery device

ABSTRACT

A separation assembly for initially keeping a first component separate from a second component includes a generally cylindrical body slidably supported within a container between the first and second components. The body includes a seal structure having an inner seal member that initially seals the first component from the second component. In response to a predetermined operating condition, the inner seal member allows the first component to flow through at least one flow path in the seal structure to mix with the second component. The body further includes a flow distributing member disposed adjacent the seal structure to evenly distribute the first component into the second component. The seal structure and the flow distributing member form a single unit.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Pat. Ser. No.09/897,422 filed on Jul. 3, 2001 now U.S. Pat. No. 6,641,561 which isrelated to provisional application Nos. 60/238,458, 60/238,448, and60/238,447, all filed on Oct. 10, 2000, all under the title of “Wet/DryAutomatic Injector Assembly,” and all of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to drug delivery devices for delivering amedicament. In particular, the present invention is directed to anautomatic injector assembly for quickly combining two components to forma liquid medicament, and delivering the liquid medicament to aninjection site.

2. Description of Related Art

An automatic injector is a device that enables intramuscular (IM) orsubcutaneous administration of a dosage of medicament. Generally, themedicament is stored as a liquid formulation which is then injectedintramuscularly. An advantage of automatic injectors is that theycontain a measured dosage of a liquid medicament in a sealed sterilecartridge. As such, automatic injectors allow for quick and simple IMinjection of a liquid medicament in emergency situations without theneed for measuring dosages. Another advantage of automatic injectors isthat the administration of the medicament is accomplished without theuser initially seeing the hypodermic needle through which the medicamentis delivered, and without requiring the user to manually force theneedle into the patient. This is particularly advantageous when themedicament is being self-administered.

There are drawbacks associated with the long-term storage of medicamentin a liquid formulation. For instance, some medicaments are not stablein solution and thus have a shorter shelf life than their solidcounterparts. To address this concern, automatic injectors have beendeveloped which store the medicament in solid form and mix the solidmedicament with a liquid solution immediately prior to injection. Theseinjectors, disclosed for example in U.S. Reissue Pat. No. 35,986,entitled “Multiple Chamber Automatic Injector,” (the disclosure of whichis incorporated herein specifically by reference), however, require theuser of the injector to manually rupture a sealing member between thesolid and liquid components and then manually shake the injector body toexpedite dissolution of the solid component prior to injection. Thisincreases the time needed to administer a dose of the medicament.However, rapid delivery of the medicament is needed in many emergencymedical situations (e.g., nerve gas and chemical agent poisoning). Otherwet/dry injection devices have been expensive to manufacture or providedunsatisfactory mixing of components prior to injection. Therefore, thereis a need for a cost-effective automatic injector that stores medicamentin solid form that does not require manual premixing by the user.

SUMMARY OF THE INVENTION

In response to the foregoing challenges, applicants have developed aninnovative automatic injection device containing a pre-loaded charge ofmedicament for automatically administering the medicament upon actuationthereof. The automatic injection device comprises a housing assembly anda chamber disposed within the housing assembly. The interior chamberincludes a dry compartment for storing a predetermined charge of drymedicament therein, and a wet compartment for storing a predeterminedamount of liquid injection solution therein. A seal structure isdisposed to seal the dry compartment from the wet compartment while theinjection device is in storage. The seal structure permits the liquidinjection solution to pass there through and mix with the dry medicamentto form a medicament mixture within the chamber during an injectionoperation. A needle assembly is in communication with the medicamentmixture during the injection operation to enable administration of themedicament mixture. A plunger is disposed within the chamber and ismovable through the chamber during the injection operation to force themedicament mixture through the needle for administration of themedicament mixture. A stored energy activation assembly is operable torelease stored energy that forces the plunger through the chamber duringthe injection operation. The seal structure is conditionable in responseto operation of the activation assembly to permit the liquid solution topass therethrough and mix with the dry medicament as aforesaid.

Other aspects and advantages of the present invention will becomeapparent from the following detailed description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in conjunction with the followingdrawing in which like reference numerals designate like elements andwherein:

FIG. 1 is a longitudinal cross-sectional view of a wet/dry automaticinjector assembly in accordance with an embodiment of the presentinvention.

FIGS. 2A-2B illustrate longitudinal cross-sectional views of needlesupport assemblies in accordance with certain embodiments of the presentinvention.

FIGS. 3A-3D illustrate cross-sectional side views of various cartridgeor chamber configurations and corresponding needle assembly optionsaccording to certain embodiments of the present invention.

FIG. 4 is an enlarged partial cross-sectional side view of a needleassembly/cartridge engagement according to the embodiment illustrated inFIG. 3A.

FIGS. 5A-5D illustrate cross-sectional side views of various embodimentsof a seal structure according to the present invention.

FIG. 6A is a longitudinal cross-sectional side view of a seal structurein accordance with another embodiment of the present invention, whereinthe movable sealing plug is in a closed sealing position blocking theflow of the liquid injection solution.

FIG. 6B is a longitudinal cross sectional side view of seal structuresimilar to 6A, but showing the movable sealing plug in an open by-passposition permitting the flow of the liquid injection solution.

FIG. 6C is a lateral cross sectional view of the seal structure of thepresent invention taken through the line 6C-6C in FIG. 6A.

FIG. 6D is a lateral cross sectional view of the seal structure of thepresent invention taken through the line 6D-6D in FIG. 6B.

FIG. 7 is a longitudinal cross-sectional view of a wet/dry automaticinjector cartridge or chamber configuration in accordance with anotherembodiment of the present invention.

FIGS. 8A and 8B are longitudinal cross sectional views of two additionalembodiments of seal structures in accordance with the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring now, more particularly to the figures, there is shown in FIG.1 an automatic injector assembly 10 in accordance with an embodiment ofthe present invention. The present invention is described in connectionwith a push button type auto injector, whereby the user removes an endcap assembly and presses a button to trigger the injection process. Thepresent invention, however, is not limited to push button type automaticinjectors; rather, it is contemplated that the present invention may beincorporated into a nose activated auto injector, as described forexample in U.S. Pat. No. 5,354,286, the disclosure of which is herebyincorporated herein by reference for such teaching.

The automatic injector assembly 10 includes a generally hollow tubularplastic housing 110. Generally, the housing 110 includes an injectionend 111 and an activation end 112, as shown in FIG. 1. In the embodimentshown, an actuator assembly 120 is inserted into the rearward end of thehousing 110. The actuator assembly 120 is received within the housing110 until flange 115 of a sleeve member 144 snaps into annular groove117 on the interior surface of housing 110. A removable safety cap 130is releasably secured to the actuator assembly 120.

The actuator assembly 120 is of any conventional type as known in theart, such as that disclosed in commonly assigned U.S. Pat. No. 5,391,151hereby incorporated by reference. The present invention employs arear-end activating device, similar to that in the aforementioned U.S.Pat. No. 5,391,151, and is therefore only briefly discussed herein. Theactuator assembly 120 includes an activation button sleeve 132 havinginternal activation surfaces 134. The activation assembly furtherincludes a plastic collet 122 with a split rearward portion formingspring fingers 136 as known in the art. The safety cap 130 has a pinportion 138 that extends between the spring fingers 136 so as to keepthem spread apart when the injector is in a storage condition. Thespring fingers 136 terminate in semi-conical configurations includingrearwardly facing sloping surfaces 139 and forwardly facing flatsurfaces 142. The collet 122 is surrounded by a cylindrical sleeve 144having inwardly extending flange 146 at the rearward end thereof. Thecollet 122 has a forward annular flange 148. A coil spring 250 surroundsthe collet 122 and is compressed between the flange 148 and flange 146.The collet flat surfaces 142 are retained in engagement with therearwardly facing surfaces of the flange 146, and thus prevented frommoving off of the flange surfaces by the pin 138 when the injector isstored.

To activate the injector, the safety pin 130 is manually pulled off ofthe rear end of the injector, thus removing pin 138 from between thefingers 136. The activation button 132 can then be pushed inwardly, andas a result of the activation surfaces thereof, 134 engages the slopingsurfaces 139 of the spring fingers 136. This forces the spring fingers136 inwards toward one another and off of the retaining surfaces of theflange 146. The compressed spring 250 is then free to release the storedenergy therein to move the collet 122 forwardly under the force of thespring to affect an injection operation as will be described later inmore detail.

It is contemplated that the actuator assembly 120 can be of any typeknown in the automatic injector art that employs releasable storedenergy. For example, rather than emptying a spring, it may employ acharge of compressed gas.

Located within the interior of the housing 110 is a vial or chamber 150,preferably made of glass, for containing both the liquid injectionsolution and the dry medicament. The chamber 150 is preferably a hollowcylinder, with a smooth cylindrical inner surface. The liquid injectionsolution is located within a wet portion 151 of the chamber 150. The drymedicament is located within a dry portion 152 of the chamber 150. It iscontemplated that the dry medicament may be in powder, lyophilized,freeze-dried, or any other solid formulation known in the art. A sealstructure 160 engages the interior side walls of the chamber 150 to sealthe dry portion 152 from the wet portion 151 and to prevent seepage ofthe liquid injection solution into the dry portion 152 prior toactivation of the injector assembly. Further, a needle assembly 140mounts to the forward end of vial or chamber 150 to inject themedicament upon activation of the injector assembly. In this embodiment,the forward end portion of the chamber 150 has an annular groove 153formed therein for attachment of the needle assembly 140. The needleassembly 140 includes a funnel-shaped needle support 143. The wide endof the needle support 143 has an annular rib 145 that is snap-fit intogroove 153 to form a seal with the chamber 150. The needle support 143can be made of a resilient plastic material, or metal with a rubber sealthat seats into groove 153. The forward narrow end 147 (see FIG. 2A) ofthe needle support 143 sealingly receives the rearward end of hollowneedle 141. The needle support 143 forms a sealed fluid channel from thechamber 150 to the needle 141. A rubber needle sheath 202 surrounds theneedle 141 and receives the narrow end 147 of the needle support 143. Afilter 190 is sealingly retained across the entire wide-end mouth of theneedle support 143 by an annular sealing washer 156.

FIGS. 2B, 3A, and 4 illustrate another embodiment of a needle assembly140 and chamber 150. The chamber 150 in this embodiment is known in theart as a dental cartridge. The dental cartridge has a cylindrical rearportion and a narrowed forward neck portion defining an outer annulargroove 153. The forward end of the dental cartridge defines an annularflange portion 154. In this embodiment, the needle support 143 has arearward annular flange 155 that receives an annular sealing member 156that surrounds both sides of flange 155. The sealing member 156 servesto seal a filter 190 over the wide end of the funnel shaped needlesupport 143. The rearward surface of the sealing member 156 is sealinglyclamped against the forward surface of chamber flange 154 by a metalretaining clamp 157 as best seen in FIG. 4.

Returning to FIG. 1, forward end 1221 of the collet 122 extends into therearward end of chamber 150 and is adapted to connect with a plunger 170rearwardly sealing the wet container 151. The plunger 170 is adapted tosealingly engage the side wall of the wet container 150 to preventleakage of the contents (e.g., liquid injection solution) of the wetcontainer 151. The plunger 170 is preferably formed from a materialhaving low frictional properties such that the collet 122 and plunger170 may easily slide within the wet container 150 when operated.Alternatively, the plunger 170 may be lubricated with silicon or othersuitable non-reactive lubricant. The movement of the collet 122 and theplunger 170 pressurizes the liquid located within the wet container 151.A suitable medicament is located within a dry container 152.

The embodiment of FIGS. 1 and 2A is advantageous in that it has an openmouth configuration wherein the needle-end of the vial or chamber is notsignificantly narrowed or tapered. Such an open mouth configurationpermits direct access to the dry portion 152 of chamber 150 for easyloading. Further, the open mouth configuration aids in preventing crosscontamination between wet portion 151 and dry portion 152 in that thedry portion 152 does not have to be filled through liquid portion 151 ofchamber 150. Needle assembly 140 can be mounted to vial or chamber 150in a snap-on configuration (FIG. 3B), an internal mount configuration(FIG. 3C), or an external needle assembly configuration (FIG. 3D).

As mentioned above, the seal structure 160 is adapted to engage theinterior side walls of chamber 150 to prevent passage of the contents(e.g., liquid injection solution) of wet portion 151 into the dryportion 152 prior to activation of the automatic injection assembly.Generally, seal structure 160 can include an outer sealing member 180, amovable sealing plug 166, a by-pass zone 165, at least one flow path167, and preferably also includes a filter or membrane 164. Withreference to FIGS. 5A-D, seal structure 160 can preferably be formed asa six piece (FIG. 5A), five piece (FIG. 5B), four piece (FIG. 5C), orthree piece (FIG. 5D) configuration.

More particularly, with reference to FIG. 5A, the outer sealingstructure 180 of the six piece configuration can comprise a two pieceannular rigid body 181 wherein members 181 a, 181 b thereof are formedinto the two piece rigid body using, e.g., annular weld connections orother bonding techniques known in the art. Outer sealing structure 180can further include multiple external sealing members 182, e.g., twoO-rings, to provide an annular sealing engagement with the inner wall ofvial or compartment 150. Seal structure 160 further includes an internalplug member 166 and a filter or dispersion membrane 164 as will bediscussed in greater detail later.

In another embodiment, as shown in FIG. 5B, rather than plural O-rings,outer sealing structure 180 can include a single external sealing member182, e.g., a unitary gasket, to provide an annular sealing engagementwith the inner wall of vial or compartment 150. External sealing member182 may optionally be secured to two piece rigid body 181 using anybonding techniques known in the art. Further, rigid body members 181 a,181 b may be shaped such that they securingly engage external sealingmembers 182 within notched recesses 183. Alternately, sealing members182 may be secured to rigid body members 181 a, 181 b by an interferencefit. As with the first embodiment, a filter or membrane 164 is clampedin place at the proximal end of flow path 167 between member 181 a andmember 181 b of the two piece rigid body.

In another embodiment, as shown in FIG. 5C, outer sealing structure 180comprises a unitary internal rigid member 181 and an external sealingmember 182. Again, internal rigid member 181 and external sealing member182 may optionally be secured together using any bonding techniquesknown in the art. Further, internal rigid member 181 and externalsealing member 182 may be formed such that they securingly engage eachother using a combination of notched recesses 183 and extendingshoulders 184. The filter or membrane 164 can be held in place betweeninternal rigid member 181 and shoulder 184 of external sealing member182. In yet another embodiment, as shown in FIG. 5D, outer sealingobject 180 can comprise a unitary external sealing member 182 which canoptionally be molded so as to accommodate filter or member 164 withinretaining recess 185. FIGS. 6A and 6B illustrate another embodiment thatis very similar to that of FIG. 5A, but provides a slightly differentshape for outer annular rigid body 181 and particularly the members 181a, 181 b thereof.

In each embodiment illustrated in FIGS. 5A-5D and 6A-6B, externalsealing member 182 is preferably formed from a non-reactive elastomermaterial which can provide for the necessary sealing engagement with theinner wall of vial or compartment 150. Further, external sealing member182 can optionally be lubricated with silicon or other suitablenon-reaction lubricant to facilitate movement of the outer sealingobject 180 forwardly within vial or compartment 150 upon receivingsufficient force as will be described. The movable sealing plug 166 ispreferably formed from a material having low frictional properties suchthat the sealing plug 166 may easily slide within outer sealing object180 when the injector is activated. The movable sealing plug 166 mayalso optionally be lubricated with silicon or other suitablenon-reactive lubricant. In each of the embodiments illustrated, theouter annular structure 180 defines an inner surface having a smoothcylindrical configuration towards the rearward portion 169 thereof, andlongitudinally extending grooves 168 towards the forward portionthereof. The grooves 168 create a flowpath or flowpaths 167 throughwhich liquid in the wet compartment 151 can bypass seal plug 166 whenthe plug 166 is moved forwardly from sealing engagement with cylindricalsurface portion 169 into the grooved portion 168. The movement of thesealing plug 166 into the by-pass area 165 opens the fluid flow path 167between wet portion 151 and dry portion 152. The movable sealing plug166 preferably includes a plurality of circumferential grooves 186 toprovide for enhanced sealing engagement and to facilitate sliding actionof the plug 166.

As mentioned above, the seal structure 160 preferably includes filter ormembrane 164 at the end of flow path 167 through which the liquidinjection solution may pass after the injector has been activated. Theliquid injection solution then enters the dry portion 152 of the chamber150 where it mixes with and dissolves the dry medicament. Moreparticularly, the filter 164 disperses the liquid injection solutionexiting the seal structure 160 to present laminar fluid flow to the fullsurface of the dry medicament, thereby wetting the entire surface of thedry medicament for rapid and complete dissolution. The filter membrane164 can be any structure that generally uniformly distributes the liquidacross the entire diameter of the chamber 150 for enhanced dissolutionof the dry medicament.

During operation, manual activation of the actuator assembly 120releases the collet 122 (as described above), which applies pressure onthe plunger assembly 170. The application of pressure on the plungerassembly 170 by the collet and spring assembly 124 moves the plunger 170in the direction of the needle assembly 140. As a result, the entirechamber 150 and needle assembly 140 are moved forwardly in the housing110 such that needle 141 pierces through the front end of sheath 202 andexits through the forward end of the housing 110, and particularlythrough a hole 204 in the front nose-cone portion 206 of the housing.The sheath 202, which serves to maintain the needle 141 sterile when theinjector is in storage, also serves as a shock absorber duringactivation as it is compressed in generally accordion like fashionbetween the nose cone 206 and needle support 143.

When the needle 141 is extended from the housing 110 and the chamber 150and needle support 143 approach the nose cone 206 portion of the housingso that further forward movement of chamber 150 is substantiallyresisted, the plunger 170 then begins to travel forwardly through thechamber 150. This pressurizes the liquid injection solution locatedwithin the wet compartment 151. With reference to FIGS. 6A-6B, theincreased pressure within the wet compartment 151 moves the sealing plug166 from a first sealed position wherein sealing plug 166 is sealinglyengaged with surface 169 of outer sealing structure 180 (FIG. 6A) to asecond by-pass position (FIG. 6B) that allows the injection solution toflow through flow path 167 created by grooves 168 and thereby throughseal structure 160.

As described above, the high pressure developed within the wet portion151 in response to movement of the collet 122 and the plunger assembly170 forces the liquid injection solution through the seal structure 160dissolving the drug into a medicament injection solution which will thenbe forced out through the needle 141 and into the patient. As the collet122 and plunger assembly 170 continue forward, the plunger 170 willeventually contact the seal structure 160, which, in a preferredembodiment, causes the seal structure 160 to move in the direction ofthe needle assembly 140. Movement of the seal structure 160 would causeany remaining solution within the portion 152 to be dispersed throughthe needle assembly 140, so as to reduce the amount of residualmedicament remaining within the chamber 150.

Referring to FIGS. 2A, 2B and 4, a membrane or filter 190 is preferablyprovided adjacent the needle assembly 140 to prevent any dry medicamentparticles from clogging the rearward end of needle 141 prior to aninjection operation. The membrane 190 may also serve to slightlyrestrict or slow injection of medicament into the patient, to facilitatemore thorough dissolution during injection.

More particularly, to prevent the passage of undissolved dry medicamentto the needle assembly 140, a medicament support 190 is preferablyprovided between the end of the dry compartment 152 and the needleassembly 140. The support 190 can serve to prevent blockage of theneedle assembly 141 by preventing the dry medicament from entering thearea surrounding the needle assembly 140 while permitting passage of themixture of dissolved medicament and liquid injection solution. Thesupport 190 may be configured as described in U.S. ProvisionalApplication No. 60/238,448, which is herein incorporated by reference ina manner consistent with this disclosure. It is contemplated thatmultiple supports 190 may be located within the dry compartment 152. Theprovision of the supports 190 may also improve the laminar flow of theliquid injection solution through the dry medicament thereby improvingdissolution.

Further, a diaphragm assembly (not shown) may also be provided adjacentthe medicament support 190, as known in the art. The diaphragm assemblyacts to prevent the passage of the liquid injection solution to theneedle assembly 140 prior to activation of the actuator assembly 120.More particularly, the diaphragm assembly will not rupture until eitherthe butt end of the needle assembly 140 ruptures the expanded diaphragmor sufficient pressure builds in the dry compartment 160 to rupture thediaphragm, again as known in the art.

As discussed above, the movement of the collet 122 causes the injectionneedle 141 of the injection assembly 140 to advance and protrude throughthe housing 110. As such, the injection of the medicament can beperformed with a simple operation. In sum, the user simply removes theend cap assembly 130, locates the injection end of the housing 110adjacent the injection site, and presses the push button 132. Thisoperation automatically triggers the operation of the drive assembly orspring 250 to advance the collet 122 causing the liquid injectionsolution located within the wet portion 151 to enter the dry portion 152through the seal structure 160. The dissolved medicament is thentransmitted through the injection needle 141 to provide the user withthe necessary dose of medicament. The automatic injector 10 inaccordance with the present invention reduces the amount of timerequired to administer medicament compared to other wet/dry injectorsand eliminates the need for mixing by the user.

The seal structure 160 advantageously enables the manufacture of asuperior wet/dry auto injector with a complementary combination ofcomponents that are either known in the art of conventionalauto-injectors or are otherwise relatively simple to manufacture. Theseal structure 160 enables sufficient mixing of wet and dry medicamentcomponents without requiring manual shaking. This mixing action isenhanced by the filter or membrane 164. In a preferred embodiment, thefilter 164 is a supported, hydrophobic acrylic copolymer cast on anon-woven nylon support. Preferably, it is a FlouRepel treated membranefor superior oleophobicity/hydro-phobicity.

In another embodiment, shown in FIG. 7, the automatic injector cartridgeincludes a needle assembly 140 located within the dry portion 152. Theneedle assembly 140 extends within the dry portion 152 to the sealstructure 160, described above in connection with FIGS. 5A-5D. Sealstructure 160 separates the dry portion 152 from the wet portion 151. Asshown in FIG. 7, the cartridge further includes a plunger 170 positionedtherein. The plunger 170 is configured to engage the collet 122 of theactivation assembly 120. As shown, the cartridge includes a sheath 301.Like the sheath 202, the sheath 301 maintains the needle 141 in asterile environment until it projects from the end of the sheath 301 inresponse to activation of the activation assembly 120. During operation,the needle assembly 140 passes through the dry portion 152 as the wetmedicament passes through seal structure 160.

In other embodiments (see FIGS. 8A and 8B), no inner plug 166 isprovided. Rather, the outer structure 180 is simply complemented by aseal membrane 226 that extends across the inner area defined by theinner surface of the outer structure. When the chamber 150 reaches theforward end of the housing during an injection operation, pressurizationof the wet compartment 151 causes the seal membrane 226 to rupture,thereby allowing the seal structure 160 to permit liquid to passtherethrough. In this embodiment, it may be desirable to provide theseal structure 160 with a pointed member 228 disposed adjacent to theseal membrane 226 to facilitate rupturing of the seal membrane uponpressurized expansion thereof during an injection operation. The member232 on which the pointed member 228 is mounted has a plurality ofpassages 234 that permits fluid to pass therethrough. Filter or membrane164 is preferably mounted distal to the passages 234 to present laminaror distributed flow to the dry medicament.

EXAMPLES

An injector according to the present invention was loaded with liquidinjection solution and dry medicament and activated with the followresults.

Loaded Dispensed Operation Dry Powder Fluid Dry Powder Fluid al Time MgMl % mg ml Secs. 531 2.7 94 497 2.3 4.0 557 2.7 93 515 2.3 4.5 582 2.692 537 2.2 4.4

It will be apparent to those skilled in the art that variousmodifications and variations may be made without departing from thescope of the present invention. For example, it is contemplated that acover assembly, described for example in U.S. Pat. No. 5,295,965 (thedisclosure of which is specifically incorporated herein by reference)may be secured to the injection end of the housing 110 after deploymentof the medicament. Furthermore, the automatic injector may furtherinclude a nipple plunger assembly, as described for example in U.S. Pat.No. 5,465,727 (the disclosure of which is specifically incorporatedherein by reference).

In yet a further embodiment, the forward dry chamber 152 contains theneedle 141, as shown in FIG. 7. The needle 141 is forced through aforward plug stopper upon initial compression of the two chamber system.As known in the art, providing the needle in the forward chamberprovides improved longitudinal compactness of the design.

In yet another embodiment, a pre-filled syringe is provided with theseal structure disposed between wet and dry components.

In further contemplated embodiments, the seal structure 160 can be usedin the same type of injector described herein, except rather thanemploying a dry (powder) medicament separated by a liquid component, afirst liquid medicament is separated from a second fluid component bythe seal structure 160. In yet another embodiment, the seal structure160 can be used in what is known in the art as a “needleless injector”where an injection can be made into a patient without a needle orcannula.

Thus, it is intended that the present invention covers the modificationsand variations of the invention, provided they come within the scope ofthe appended claims and their equivalents.

1. A separation assembly for a container that separates a firstcomponent from a second component and that allows the first component tobe mixed with the second component upon occurrence of a predeterminedoperating condition, the separation assembly comprising: first andsecond open ends and a generally cylindrical hollow body there betweenslidably supported within the container between the first component andthe second component, the hollow body having an inner sidewall surfaceand a flow path extending longitudinally from the first open end to thesecond open end, the flow path formed entirely by one or morelongitudinal structures in the hollow body; a one-piece inner sealmember disposed at the first open end to seal the flow path beforeoccurrence of the predetermined operating condition; and a flowdistributing member disposed at the second open end and operative toreceive there through and distribute the first component into the secondcomponent upon occurrence of the predetermined operating condition;wherein: the inner seal member is operative to allow the first componentto flow through the flow path and through the flow distributing memberto mix with the second component in response to an occurrence of thepredetermined operating condition; and a plurality of circumferentialportions of the periphery of the inner seal member maintains contactwith the inner sidewall surface at all times.
 2. The separation assemblyaccording to claim
 1. wherein the flow distributing member comprises afilter.
 3. The separation assembly according to claim 1, wherein theinner seal member comprises a movable plug.
 4. The separation assemblyaccording to claim 1, further comprising an outer seal member that hasan outer periphery that forms a peripheral seal with an interior wall ofthe container.
 5. The separation assembly according to claim 1, whereinthe inner seal member comprises a burstable membrane operative to burstin response to an occurrence of the predetermined operating condition.6. The separation assembly according to claim 1, wherein the first orsecond component is a medicament.
 7. The separation assembly accordingto claim 1, wherein the first component is a liquid.
 8. The separationassembly according to claim 1, wherein the second component is a solid.9. The separation assembly according to claim 8, wherein the solid is apowdered, lyophilized, or freeze-dried substance.
 10. The separationassembly according to claim 1, wherein the flow distributing membercomprises a membrane through which a liquid solution is passable. 11.The separation assembly according to claim 1, wherein the predeterminedoperating condition is activation of an injector activation assembly incommunication with the container.
 12. The separation assembly accordingto claim wherein the inner seal member is slidably engaged with thehollow body.
 13. The separation assembly according to claim 1, whereinthe hollow body comprises two O-rings to provide annular sealingengagement with an interior wall of the container.
 14. The separationassembly according to claim 1, wherein the hollow body comprises aunitary gasket to provide annular sealing engagement with an interiorwall of the container.
 15. An automatic injector comprising: a housing;a chamber disposed in the housing, the chamber having at least oneopening therein and containing a medicament, the medicament beingrearwardly confined by a plunger; an actuation assembly disposed in thehousing, the actuation assembly comprising a stored energy sourcecapable of being released to drive the plunger through the chamber; aneedle assembly in communication with the chamber, the needle assemblycomprising a needle support forming a seal with the chamber, the needleassembly further comprising a needle received in the needle support, theneedle configured to expel the medicament when the plunger is driventhrough the chamber; and a separation assembly that separates a firstcomponent of the medicament from a second component of the medicamentand that allows the first component to be mixed with the secondcomponent upon occurrence of a predetermined operating condition, theseparation assembly comprising: first and second open ends and agenerally cylindrical hollow body there between slidably supportedwithin the chamber between the first and second components, the hollowbody having an inner sidewall surface and a flow path extendinglongitudinally from the first open end to the second open end, the flowpath formed entirely by one or more longitudinal structures in thehollow body; a one-piece inner seal member disposed at the first openend and having a peripheral surface in lateral continuous 360 degreecontact with the inner sidewall surface to seal the first component fromthe second component before occurrence of the predetermined operatingcondition, the inner seal member operative to allow the first componentto flow through the flow path to mix with the second component inresponse to an occurrence of the predetermined operating condition, theperipheral surface of the inner seal member in lateral intermittent 360degree contact with the inner sidewall surface to allow the firstcomponent to flow through the flow path to mix with the secondcomponent; and a flow distributing member disposed at the second openend and operative to receive there through and distribute the firstcomponent into the second component in response to an occurrence of thepredetermined operating condition.
 16. The automatic injector accordingto claim 15 wherein the inner seal member comprises a movable plug. 17.The automatic injector according to claim 15 wherein the separationassembly further comprises an outer seal member that has an outerperiphery that forms a peripheral seal with an interior wall of thechamber.
 18. The automatic injector according to claim 15 wherein thefirst component is a liquid and the second component is a solid.
 19. Theautomatic injector according to claim 15 wherein the flow distributingmember comprises a membrane through which a liquid solution is passable.